Showing papers by "R.D. Stambaugh published in 1986"
TL;DR: In this article, the authors performed extensive energy confinement experiments on the Doublet III tokamak with up to 8 MW of both hydrogen and deuterium neutral beam heating power.
Abstract: Over the past three years, extensive energy confinement experiments have been performed on the Doublet III tokamak with up to 8 MW of both hydrogen and deuterium neutral beam heating power. These experiments covered a wide range of plasma parameters and almost a continuum of magnetic configurations from limited to fully diverted. It has been found that the global energy confinement time is linearly proportional to the plasma current and decreases with the application of neutral beam power for all configurations and beam species studied. The majority of our confinement experiments were conducted with discharges limited toward the outside of the vacuum vessel and heated with hydrogen neutral beams. With respect to this standard operating mode, several operating regimes were found with improved values of energy confinement time. Generally, deuterium neutral beam heating is superior to hydrogen beam heating and divertor operation yields superior confinement as compared to limiter operation. Our experiments also indicate that discharges limited toward the inside of the vacuum vessel exhibit somewhat better confinement relative to discharges limited toward the outside. Accordingly, the highest energy confinement values are obtained in high current, well diverted, deuterium beam heated discharges. Deuterium beam heated discharges limited toward the inside yield normalized energy confinement values similar to those from hydrogen beam heated divertor discharges.
26 citations
TL;DR: The Compact Ignition Tokamak (CIT) as discussed by the authors is a tokamak with a high filed (10 T), high current (10 MA), poloidal divertor, and liquid-nitrogen-cooled coils.
Abstract: The goal of the Compact Ignition Tokamak (CIT)d program is to provide a cost-effective route to the production of a burning deuterium-tritium plasma, so that alpha-particle effects may be studied. A key issue to be studied in the CIT is whether alpha power behaves like other power sources in affecting tokamak plasma confinement. The program is managed by the Princeton Physics Laboratory and includes broad community involvement. Guidelines for the preliminary design effort have been provided by the Ignition Technical Oversight Committee in discussion with the tokamak community. The reference design is a tokamak with a high filed (10 T), high current (10 MA), poloidal divertor, and liquid-nitrogen-cooled coils. It is a small, high-power-density device of the type proposed by Bruno Coppi (MIT). It has a major radius of 1.23 m, a minor radius of 0.43 m, and plasma elipticity of 1.8. This paper reviews the aims of the program and the basis for the physics guidelines. The role of the CIT in the longer-term tokamak program is briefly discussed. 23 refs., 9 figs., 1 tab.
7 citations
TL;DR: In this paper, the linear and nonlinear characteristics of pressure-driven magnetohydrod dynamic instabilities are examined for a high-beta ( beta T=4.5%) limiter discharge and for a typical high confinement time diverted discharge in Doublet III.
Abstract: The linear and nonlinear characteristics of pressure-driven magnetohydrodynamic instabilities are examined for a high-beta ( beta T=4.5%) limiter discharge and for a typical high confinement time diverted discharge in Doublet III. These discharges are found to be linearly unstable to high-beta external kink-tearing modes even with the stabilizing influence of a conducting shell and a conducting mantle. Nonlinear calculations show that tearing mode islands are too small to overlap, possibly related to the experimentally observed stability against disruption at the discharge time of interest.
3 citations